cmp
[options] file1 file2Compare file1 with file2. Use standard input if file1 or file2 is -
. See also comm and diff. The exit codes are as follows:
0 | Files are identical. |
1 | Files are different. |
2 | Files are inaccessible. |
-l
For each difference, print the byte number in decimal and the differing bytes in octal.
-s
Work silently; print nothing, but return exit codes.
Print a message if two files are the same (exit code is 0):
cmp -s old new && echo 'no changes'